Grouped Licenses Network Analysis

Based on Stoll et al. 2016 license categories

Author

cslovas

License Type Target Species Stoll 2016 Grouping
Aquaculture license Aquaculture Aquaculture
Commercial fishing crew Finfish Commercial Fishing
Commercial fishing single Finfish Commercial Fishing
Commercial pelagic and anadromous crew Pelagic/Anadromous Pelagic & Anadromous
Commercial pelagic and anadromous single Pelagic/Anadromous Pelagic & Anadromous
Commercial shellfish Shellfish Shellfish
Commercial shrimp crew Shrimp Northern Shrimp
Commercial shellfish + 70 Shellfish Shellfish
Commercial shrimp single Shrimp Northern Shrimp
Commercial shellfish under 18 Shellfish Shellfish
Elver dip net Elver Elver
Elver dip net crew Elver Elver
Elver 1 fyke net Elver Elver
Elver 1 fyke net crew Elver Elver
Elver 2 fyke net Elver Elver
Elver 2 fyke net with crew Elver Elver
Elver dip net 1 fyke net Elver Elver
Elver dip net 1 fyke net crew Elver Elver
Eel pot Eel Eel
Green crab Green crab Green crab
Lobster crab apprentice Lobster Lobster Apprentice & Student
Lobster crab apprentice + 70 Lobster Lobster Apprentice & Student
Lobster crab apprentace under 18 Lobster Lobster Apprentice & Student
Lobster crab class i Lobster Lobster Class I
Lobster crab class ii Lobster Lobster Class II
Lobster crab class ii + 70 Lobster Lobster Class II
Lobster crab class iii Lobster Lobster Class III
Lobster crab class iii + 70 Lobster Lobster Class III
Lobster crab + 70 Lobster Lobster Crab
Lobster crab student Lobster Lobster Apprentice & Student
Lobster crab under 18 Lobster Lobster Apprentice & Student
Mussel dragger Mussel Mussel
Menhaden commercial Menhaden Menhaden
Menhaden non commercial Menhaden Menhaden
Mussel hand Mussel Mussel
Marine worm digging Marine worm Marine worm
Quahog (mahogany) Quahog clam Mahogany Clam
Sea cucumber drag Sea cucumber Sea Cucumber
Scallop dragger Scallop Scallop (Dragger)
Scallop diver Scallop Scallop (Hand)
Scallop with tender Scallop Scallop (Tender)
Spat Spat Spat
Sea urchin dragger Sea urchin Sea Urchin (Dragger)
Sea urchin diver Sea urchin Sea Urchin (Hand)
Sea urchin raking Sea urchin Sea Urchin (Hand)
Surf clam boat Surf clam Surf Clam
Sea urchin with tender Sea urchin Sea Urchin (Tender)
Seaweed Seaweed Seaweed
Seaweed supplemental Seaweed Seaweed

Portfolio by License Subdivisions

Using Theresa Burnham’s code for building the individual license portfolio, license types were grouped license divisions as described in Stoll et al. 2016. A binary matrix was created, whereas 1 denotes an individual license holding for a corresponding year and 0 denotes no license held. With this co-occurrence matrix, we can quantify which license types were held together over the past 30 years and how those holdings have changed.

Annual Species Metrics

Degree centrality

“The degree of a node is the number of other nodes that single node is connected to.

Important nodes tend to have more connections to other nodes. Highly connected nodes are interpreted to have high degree centrality.”

Betweeness

“[Betweenness] ranks the nodes based on the flow of connections through the network. Importance is demonstrated through high frequency of connection with multiple other nodes. Nodes with high levels of betweenness tend to serve as a bridge for multiple sets of other important nodes.” Source

Annual Network Plots

Edge Density and Modularity